Loss of Gprasp1 or Gprasp2 effects HSPCs migration, homing, and niche retention. (A) Control, Gprasp1, or Gprasp2-shRNA-treated HSPCs were assayed for SDF-1 responsiveness in trans-well migration assays. Each trans-well bottom chamber was tested for colony-forming units (CFUs) as a readout for migrating cells. (B) LT-HSCs CD45.2⁺mCherry⁺ frequency in the BM of recipients of control, Gprasp1- or Gprasp2-shRNA–treated LSK cells 3 hours posttransplant. (C) Experimental schematic. CD45.2⁺ LSK cells transduced with Gprasp1, Gprasp2, or control shRNAs were transplanted into lethally irradiated CD45.1/CD45.2⁺ mice. After stable engraftment, recipient BM was mobilized by cytoxan (Cy)/G-CSF (G) treatment. (D) LT-HSC CD45.2⁺mCherry⁺ frequency in PB, spleen, and BM at 0, 2, and 4 days postmobilization. (E) CFUs in the PB of mobilized recipients described in panel C. Data in panels B through E from ≥5 independent transplants. N ≥ 3 recipients per condition per transplant. Data represented as mean plus or minus SEM. *P < .05; ** P < .005; ***P < .001 significantly different to control.